The word is used frequently in the discipline of philosophy. It includes semantics or semiotic, logic, and some other more technical disciplines like phenomenology. When writing a complete philosophy, a perenial question is whether to begin with epistemology or metaphysics, as each presumes the other. Science often assumes its epistemology with a "realism" that assumes some reality is out there that can be studied. Scientism takes it a step further and says that is the only true knowledge. It is probably safer to assume science is one valid source of knowledge, but there may be others.

In theology there is a similar problem of whether one begins with a docrine of God or of revelation. On the one hand, how can we say anything about a god or gods without a universal or specific revelation. On the other hand, doesn't a theory of revelation imply in itself something of the nature of the god in question? Namely, that the god reveals himself or herself.

A basic question in any philosophy or theology is the role of authority. Is the Bible, Quran, Baghavad-Gita authoritative, and if so, in what sense? Likewise in science, we find devotees who feel constrained to accept Einstein and Freud's teachings as authoritative to the point some feel a struggle to disagree with them.